JP2016124196A - Thermochromic writing instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermochromic writing instrument of which a pen point has elasticity such as a pen point of a fountain pen.SOLUTION: A thermochromic writing instrument 1 has a pen point 4 which can jet thermochromic ink to the front side of a barrel and allows handwriting of the thermochromic ink to be thermally changed by friction heat generated when rubbing the handwriting. Therein, the pen point 4 is integrated by superimposing a plurality of thin plate metal members 41, 42 formed of tapered parts 41b, 42b on the front side to each other and welding a pen point 43 onto tips of the tapered parts 41b, 42b, a part between the thin plate metal members 41, 42 is formed as an ink channel 7 of the fine gap state and a slit 43b extended longitudinally is formed on the pen point 43.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a thermochromic writing instrument capable of thermally changing the handwriting with frictional heat generated by rubbing the handwriting of a thermochromic ink.

  Conventionally, there has been known a thermochromic writing instrument with a friction part that thermally discolors handwriting written on paper using a thermochromic ink with frictional heat when rubbing. For example, Patent Document 1 discloses reversible thermochromic. The structure where a friction body is provided at the rear end of the writing instrument shaft and the top of the writing instrument cap is incorporated, and the writing instrument with the thermochromic ink written on the writing instrument is provided on the writing instrument. A structure that is thermally discolored by a friction body is disclosed. This thermochromic writing instrument has very convenient properties, and it is actually commercialized that the handwriting written on paper with the writing instrument can be rubbed and discolored by the friction part provided on the writing instrument. And satisfied with a wide range of users.

On the other hand, since fountain pens that use water-based inks that have been used for a long time have a unique writing taste due to the elasticity of the nib, thermochromic writing instruments that use the thermochromic inks are expected to be in the form of fountain pens. Became.
However, in the above-mentioned thermochromic ink, microcapsules are used as pigments, and when this is used as a water-based ink for a fountain pen, unlike dyes, once the ink has dried, it will be exposed to moisture later. Even so, the redispersibility of the pigment is poor. In addition, with a fountain pen, the viscosity is increased and the surface tension is lowered, so that it is not suitable to add a moisturizing agent. As a result, drying of water-based ink using microcapsules as a pigment has been a problem.
In addition, the pen tip of the fountain pen is provided with a slit extending long in the center of the pen body in order to apply capillary force to flow ink to the tip of the pen tip or to give elasticity to the pen tip, If the ink is dried even in a part of the long cut, it becomes impossible to write, and thus it is particularly difficult to employ water-based ink using a microcapsule at the nib of a fountain pen as a pigment.

  Therefore, the inventors of the present application superimpose a plurality of thin sheet metal members described in Patent Document 2, and pay attention to the pen tip formed over the entire length as a minute gap-shaped ink flow path between the thin sheet metal members, It came to this invention.

JP 2004-148744 A JP-A-8-52977

  An object of the present invention is to obtain a thermochromic writing instrument in which the nib has elasticity similar to that of a fountain pen nib.

The present invention
“1. A thermochromic property that has a nib that can eject thermochromic ink in front of the shaft cylinder, and that can rub the handwriting of the thermochromic ink and heat discolor the resulting handwriting by frictional heat. In the writing instrument, the pen nib is formed by superimposing a plurality of thin plate metal members formed with a tapered portion on the front side, and by integrating a pen point at the tip of the tapered portion, and between the thin plate metal members. A thermochromic writing instrument, wherein the pen point is formed as a minute gap-like ink flow path and a slit extending in the front-rear direction is formed at the pen point.
2. 2. The thermochromic writing instrument according to claim 1, wherein the pen point slit is formed between the tip of the pen point and the ink flow path.
3. 3. The thermochromic writing instrument according to claim 1 or 2, wherein the thermochromic writing instrument has a cap, and a recess is provided inside the cap to elastically deform and cover the pen point.
4). A friction body made of an elastic material capable of thermally discoloring the handwriting of the thermochromic ink by rubbing the handwriting of the thermochromic ink at the tip of the cap is mounted, and the concave portion is formed in the friction body. The thermochromic writing instrument as described in 3 above, wherein It is.

The average particle size of the thermochromic microcapsule particles to be contained in the thermochromic ink is 0.1 to 5.0 μm, and preferably 0.5 to 3 μm. In systems where the average particle diameter exceeds 3.0 μm, the outflow from the capillary gap decreases, and in systems where the average particle diameter is less than 0.5 μm, it is difficult to exhibit high color development.
The “average particle diameter” defined in the present invention is a value obtained by using a laser type particle size distribution analyzer LA-300 (volume basis) manufactured by Horiba, Ltd., and using the median diameter as the average particle diameter.

In addition, as the thermochromic ink, a general-purpose ink can be applied regardless of reversible and irreversible, and the color of the handwriting can be changed, the color of the handwriting can be changed, and the color can be erased and colored by heating the handwriting by frictional heat. Can be applied selectively.
In particular, the change in the handwriting can be stably expressed for a long time without causing a change in composition by encapsulating the thermochromic composition in a microcapsule.
The thermochromic composition encapsulated in the microcapsule pigment includes (a) an electron-donating color-forming organic compound, (b) an electron-accepting compound, from the viewpoints of repeated usability and temperature change accuracy. (C) A reversible thermochromic composition comprising a reaction medium that determines the temperature at which the two color reactions occur is preferred.

Specific examples of the microcapsule pigment encapsulating the reversible thermochromic composition include predetermined ones described in JP-B-51-44706, JP-B-51-44707, JP-B-1-29398, and the like. Before and after the temperature (discoloration point), the color changes in the temperature range above the high temperature side discoloration point, and the color develops in the temperature range below the low temperature side discoloration point. There is only one specific state, and the other state is maintained while the heat or cold required to develop the state is applied, but at room temperature if the heat or cold is no longer applied It is possible to apply a microcapsule pigment encapsulating a heat decoloring type reversible thermochromic composition having a characteristic (ΔH = 1 to 7 ° C.) having a relatively small hysteresis width that returns to the state shown in FIG.
Furthermore, relatively large hysteresis characteristics (ΔH = 8 to 50) described in Japanese Patent Publication No. 4-17154, Japanese Patent Application Laid-Open No. 7-179777, Japanese Patent Application Laid-Open No. 7-33997, Japanese Patent Application Laid-Open No. 8-39936, and the like. C.) can also be applied.

  Further, it exhibits a large hysteresis characteristic described in JP-A-2006-137886, JP-A-2006-188660, JP-A-2008-45062, JP-A-2008-280523, etc., that is, due to temperature change. The shape of the curve plotting the change in color density follows a very different path when the temperature is raised from the lower temperature side than the color change temperature range, and vice versa. The reversible heat has a color memory in a specific temperature range (substantially two-phase holding temperature range) when the color development state in the low temperature range below the complete color development temperature or in the high temperature range above the complete color erase temperature. It is also possible to use a microcapsule pigment in which a color changing composition is encapsulated.

  Specifically, as a reversible thermochromic composition having color memory, which is applied to the thermochromic writing instrument of the present invention, a complete color development temperature is a temperature that can be obtained only in a freezer room, a cold district or the like, that is, −50 to 0 ° C., preferably −40 to −5 ° C., more preferably −30 to −10 ° C., and a complete decolorization temperature obtained from a frictional heat generated by a friction body, a heating body such as a hair dryer, that is, 50 to 95 ° C, preferably 50 to 90 ° C, more preferably 60 to 80 ° C, and ΔH value of 40 to 100 ° C to maintain colors that are exhibited in the normal state (daily life temperature range) It can function effectively.

For thin metal members, iron alloys, especially stainless steel, copper alloys, especially phosphor bronze, are superior in terms of springiness and formability. Among them, stainless steel has high corrosion resistance, and unlike phosphor bronze, surface treatment such as plating is performed. It is not necessary and suitable. In addition, a flat metal member is suitable because it is easy to mold. Moreover, although the form where the surface curved like the pen point of a fountain pen may be sufficient, it is necessary to form in the form where several sheet metal members each overlap.
The pen point can be a white metal group, such as a Ru-based alloy, an Os-based alloy, a W-based alloy, or a Cr-based alloy, and can be appropriately set in view of the material of the thin metal member to be welded. Also, the method for welding the pen point to the thin metal member includes welding or brazing, and may be appropriately selected according to the material of the thin metal member and the pen point.

A minute gap-shaped ink flow path formed between a plurality of thin metal members is connected to an ink tank in the shaft cylinder so that ink can be supplied to a pen point slit by capillary force.
In addition, the ink exposed to the outside outside the ink flow path formed between a plurality of thin sheet metal members will be dried, but the dried ink will seal the inside of the ink flow path. Ink positioned at the center of the ink flow path leading to the ink does not dry, and writing can be performed without interrupting the ink.

  Also, by forming the pen point slit in a short section from the tip of the pen point to the ink flow path between the thin metal members, the amount of ink dried in the pen point slit is reduced, and if the ink in the slit is Even if it dries, the ink is dried only at the tip of the slit, so when the pen point slides on the writing surface at the time of writing, the dried ink peels off by touching the writing surface, You will be able to start writing.

In the case where a recess for covering the pen point is provided inside the cap attached to the pen tip side, the material for forming the recess is preferably an elastic synthetic resin (rubber or elastomer), for example, a silicon resin or an SBS resin. (Styrene-butadiene-styrene copolymer), SEBS resin (styrene-ethylene-butylene-styrene copolymer), fluorine resin, chloroprene resin, nitrile resin, polyester resin, ethylene propylene diene rubber (EPDM), etc. It is done.
In addition, when the concave portion is formed on a friction body made of an elastic material capable of thermally changing the handwriting by frictional heat generated by rubbing the handwriting of the thermochromic ink, the synthetic resin having the elasticity described above Among them, a low-abrasion elastic material that does not cause wear debris (erasure debris) at the time of friction is preferable, not a high-abrasion elastic material (for example, an eraser).

  In addition, by forming the pen point in a spherical shape and forming the pen point at the axial center position of the writing instrument body, when the cap is attached to the writing instrument body, the concave portion of the cap is only the pen point of the pen tip. Therefore, even if the entire nib is plate-shaped, it can be used in a mounting method in which the pen nibs are rotated relative to each other like screwing.

  The thermochromic writing instrument of the present invention has elasticity as a pen tip of a fountain pen, and can prevent ink ejection failure due to drying of the thermochromic ink.

It is a whole perspective view of the thermochromic writing instrument of a present Example. It is a principal part enlarged view of the thermochromic writing instrument of FIG. It is a longitudinal cross-sectional view of the thermochromic writing instrument of FIG.

Next, specific examples of embodiments of the present invention (hereinafter referred to as examples) will be described with reference to the drawings, but the present invention is not limited to the following examples.
In addition, in order to make the explanation easy to understand, the same numbers are given to the same members and the same parts in the drawings. In the description of the present embodiment, the side with the pen tip is expressed as the front side, and the opposite side is expressed as the back side.

  FIG. 1 is an overall perspective view of the thermochromic writing instrument of the present embodiment, FIG. 2 is an enlarged view of a main part, and FIG. 3 is a longitudinal sectional view. The thermochromic writing instrument 1 of the present embodiment has a storage groove 5a formed by screwing the neck tube 3 in front of the shaft tube 2 and forming the pen tip 4 over the entire length of the pen core 5 press-fitted into the neck tube 3. The writing tool main body 10 is configured by fitting the connecting portion 3 a formed in the rear portion of the neck tube 3 into the ink tank 6 disposed in the shaft tube 2.

  The pen tip 4 includes two thin plate members 41 and 42 and a pen point 43 provided at the tip of the two thin plate members 41 and 42. The thin plate members 41 and 42 of the present embodiment are made of stainless steel, and have straight portions 41a and 42a that are fitted into the storage grooves 5a of the pen core 5, and tapered portions 41b and 42b formed in front thereof. . The pen point 43 is made of a Ru-based alloy, and is welded to the tips of the tapered portions 41b and 42b so that the two thin plate members 41 and 42 are integrated.

A minute gap-shaped ink flow path 7 is formed between the two thin plates 41 and 42 that are integrated, and is connected to a slit 43 b formed between the tip 43 a of the pen point 43 and the ink flow path 7. Thus, thermochromic ink (not shown) in the ink tank 6 is supplied to the tip 43a of the pen point 43 by capillary force.
As shown in FIG. 2, the pen tip 4 formed of the two thin plate members 41 and 42 has elasticity that can swing in the vertical direction, like the pen tip of the fountain pen.

The thermochromic writing instrument 1 has a cap 8 that covers the nib 4, and the cap 8 is formed at the rear end of the friction body 9 made of a styrene-based thermoplastic elastomer in a through hole 8 a provided at the tip. The latching portion 9a is inserted in a retaining state. A concave portion 9b is provided at the rear end of the locking portion 9a, and the concave portion 9b is elastically deformed to seal the slit 43b of the pen point 43 when the pen tip 4 is inserted from the opening 8b of the cap 8. It is.
The friction body 9 can rub the handwriting written with the thermochromic ink at the top portion 9c, and can be thermally discolored by frictional heat generated at that time.

  In this embodiment, the pen point 43 of the nib 4 is spherical and formed at the position of the axial center of the writing instrument body 10, and the recess 9 b of the cap 8 covers only the pen point 43. Therefore, even if the pen tip 4 is entirely plate-shaped, the male screw portion 3b formed on the outer surface of the neck tube 3 and the female screw portion 8c formed on the inner surface of the cap 8 are screwed together, so that the pen point 43 Could be sealed with the recess 9b.

1 ... thermochromic writing instrument, 10 ... writing instrument body,
2 ... shaft tube,
3 ... neck tube, 3a ... connection part, 3b ... male screw part,
4 ... nib,
41, 42 ... thin plate material, 41a, 42a ... straight portion, 41b, 42b ... tapered portion,
43 ... pen point, 43a ... tip, 43b ... slit,
5 ... Pen core, 5a ... Storage groove,
6 ... Ink tank,
7: Ink flow path,
8 ... Cap, 8a ... Through-hole, 8b ... Opening, 8c ... Female screw part,
9 ... friction body, 9a ... locking portion, 9b ... concave portion, 9c ... top portion.

Claims (4)

In the thermochromic writing instrument that has a nib capable of discharging thermochromic ink in front of the shaft cylinder, and that can rub the handwriting of the thermochromic ink and heat-discolor the handwriting by frictional heat generated at that time, The pen tip overlaps a plurality of thin metal plates with a tapered portion formed in front, and a pen point is welded to the tip of the tapered portion so as to be integrated, and a small gap is formed between the thin metal members. A thermochromic writing instrument, characterized in that it is a pen tip formed as an ink flow path and having a slit extending forward and backward at the pen point. The thermochromic writing instrument according to claim 1, wherein the pen point slit is formed between the tip of the pen point and the ink flow path. The thermochromic writing instrument according to claim 1 or 2, wherein the thermochromic writing instrument has a cap, and a recess for elastically deforming and covering the pen point is provided inside the cap. A friction body made of an elastic material capable of thermally discoloring the handwriting of the thermochromic ink by rubbing the handwriting of the thermochromic ink at the tip of the cap is mounted, and the concave portion is formed in the friction body. The thermochromic writing instrument according to claim 3, wherein the thermochromic writing instrument.

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